Chapter 22 - The Respiratory System Flashcards
Functions of the Respiratory System
Gas exchange between the air and blood. Conduction of air to exchange surfaces. Protection of respiratory surfaces. Sound production. Olfaction. pH regulation, CO2 determines the pH.
Stages of Respiration
- Pulmonary Ventilation: air is being moved in and out of the lungs.
- External Respiration: exchange of O2 and CO2 between the blood and the lungs
- Transport of O2 and CO2 in the blood.
- Internal Respiration: exchange of O2 and CO2 between the blood and the body tissues
- Cellular Respiration: Utilization of O2 by the cells and the production of CO2 by the cells.
Respiratory Zone
the site of gas exchange which involves the respiratory bronchiole, alveolar ducts, and alveoli.
Conducting Zone
All of the other passageways in the system
Nasal Cavity
Moistens air, filters air, resonating chamber, and olfactory receptors.
The Pharynx
A muscular tube in the throat region. It is used by the respiratory and digestive system. Divided into 3 regions. The nasopharynx, the oropharynx, and the laryngopharynx.
Nasopharynx
Lies immediately behind the nasal cavity. It is lined by pseudostratified ciliated epithelium. Contains the auditory tubes, the pharyngeal tonsils, and the uvula.
Oropharynx
Extends from the soft palate to the laryngopharynx. Mostly stratified squamous epithelium. The mouth opens to here, the lingual tonsils are on the base of the tongue, and the palatine tonsils are on the side walls.
The Larynx
A structure that connects the laryngopharynx to the trachea. It provides an open airway, acts as a switching mechanism and aids in voice production.
Thyroid Cartilage
A U-shaped shield. It consists of hyaline cartilage. it doesn’t completely circumvent the larynx. The location of the Adam’s apple.
Cricoid Cartilage
Makes a complete ring around the larynx. Made of hyaline cartilage
Epiglottis
A leaf-shaped cartilage that guards the opening to the larynx. It helps keep the airway open and is part of the voice production.
Glottis
The opening to the larynx. It has 2 horizontal folds of a mucus membrane.
Vocal Cords
Two sets. False, the top two folds, and true, the bottom two folds.
Laryngitis
Inflammation of the mucus membrane that covers the folds.
Trachea
About 11 centimeters and all hyaline cartilage. The beginning of the lower respiratory tract. Lined with stratified squamous epithelium above the trachea and gives way to pseudostratified ciliated columnar epithelium.
Function of the trachea’s C-shaped rings
They keep the trachea from collapsing and allows it to expand when the esophagus expands with food.
Heimlich Maneuver
An abdominal thrust where air, and thus any trapped material, is forced out of the trachea.
Primary Bronchi
Two branches, left and right. Each supplies one lung.
Secondary Bronchi
Also called lobar bronchi. Each supplies a lobe. 3 on the right, the superior, middle, and inferior. 2 on the left, superior and inferior
Tertiary Bronchi
Also called segmental bronchi. Each supplies a specific bronchopulmonary segment.
Respiratory Structures
Lack cartilage. This is the beginning of the alveolar system, where respiration takes place. In the respiratory bronchioles, there is now ciliated columnar epithelium
Bronchioles
The respiratory structures that branch into the alveolar ducts leading to the sacs where gas exchange occurs.
Alveolus
The functional unit of the lung. It is simple squamous epithelium and has free roaming macrophages. It has septal cells which produce surfactant a material that rejects water.
Respiratory Membrane
Formed by the alveolar wall and the capillaries where gas exchange occurs by simple diffusion. O2 comes from the alveolus to the blood, and CO2 leaves the blood and goes into the alveolus.
ANS Regulation
Regulates the smooth muscle layer surrounding the bronchioles. The sympathetic division causes the smooth muscle to relax and the parasympathetic division causes smooth muscle to contract.
Lungs and Pleural Membranes
A large amounts of connective tissue with elastic fibers helps give the lungs their elastic recoil
Lung Lobes
3 on the right, 2 on the left. Left ones are smaller because the heart is located there.
Pleura
A double layered serous membrane. Two layers:
- parietal: lines the thoracic wall and mediastinum. It goes around the heart and lungs
- visceral: also called the pulmonary pleura. It covers the external lung surface.
Pleural Fluid
Fluid in the pleural cavity between the two layers. It’s secreted for lubrication, and allows for the lungs to glide over the thorax
Atmospheric Pressure
The pressure surrounding the body everyday. Usually about 760 mmHg.
Intrapulmonary Pressure
Rises and falls with the phases of breathing. It equals out with the atmospheric pressure.
Intrapleural Pressure
Always changing, but it’s always 2-4 mm less than in the alveoli. This keeps the lungs from collapsing.
Factors holding the lungs to the thoracic wall
- adhesive force of the pleural fluid
- absorption of gases in the pleural space into the capillary blood
- the positive pressure in the lungs
Factors acting to poyull the lungs away from the thoracic wall
- the recoil tendency of the lungs
- the surface tension in the alveoli
Inspiration
- Inhaling. The diaphragm contracts, the thoracic cavity volume increases.
- Contraction of the external intercostal muscles raises, or elevates, the rib cage and expands the diameter of the thorax
Expiration
Normally passive. Inspiratory muscles relax, lungs recoil, volume decreases. Pressure increases to exceed atmospheric pressure so gases flow out of the lungs.
Prevention of Lung Collapse
The alveoli have a layer of moisture in their inner surface and which would cause it to collapse and stick together, but it has surfactant, a phospholipid protein which reduces surface tension.
Respiratory Passageway Resistance
Friction which makes breathing more strenuous
Lung Compliance
The ease at which the lungs can be expanded, also called distensibility.
Lung Elasticity
Essential for expiration. When it declines, it destroys distensibility.
Total Lung Capacity
The total volume of air that the lungs can hold
Residual Air Volume
The amount of air left following a maximum expiration
Vital Capacity
The total/maximum amount of air moved in a respiratory cycle.
Tidal Volume
The amount normally inspired during quiet breathing
Inspiratory Reserve Volume
The volume that can be forcefully inspired following a normal expiration
Expiratory Reserve Volume
The volume that can be forcefully expired following a normal inspiration
Dead Air Space
All the gas exchange occurs across the alveoli, but the remainder of the bronchial ree and other parts of the system constitute dead space.
Minute Respiratory Volume
The total amount of gas that can be exchange in one minute
Alveolar Ventilation
The actual amount of atmospheric air entering the alveoli per minute.
Nerual Contol of Respiration
Respiratory muscles are responsible for inspiration and expiration under the control of the nervous system. The integrating centers are in the medulla and pons
Inspiratory Area
The dorsal respiratory group. This center initiates inspiration by sending impulses to the diaphragm and the external intercostal muscles
Expiratory Area
Not normally active during normal breathing. Only activated during forced breathing.
Pneumotaxic Center
Fine tunes breathing and prevents lung overinflation
Apneusitc Center
Prolongs inspiration
Hering-Breuer Reflex
A protective response against over-inflation
Cerebral Effects
The cerebrum has an effect, but it cannot override the medullary center. The medulla has the final say.
Hypothalmic Contorls
Emotional and pained reactions can influence respiration.
Chemical Control
Respiratory muscles that actually cause ventilation are under chemical control, the concentration of O2 and CO2 in the blood.
Carbon Dioxide
The direct effect. The H+ produced by the reaction of CO2 and H2O, along with pH sensitive cells excite the inspiratory center. Therefore CO2 is considered to be a major factor controlling respiration.
Oxygen
The indirect effect. There are 2 chemoreceptors, the aortic and carotid bodies. They are sensitive to arterial O2 concentration. If O2 concentration decreases, a nervous reflex will speed up the activity of the inwaspiratory center. The O2 effect is very weak compared to the CO2 effect.
Swallowing
A special reflex that avoids the passage of food into the lower respiratory tract. It activates stretch receptors in the wall of the pharynx, causing the epiglottis to cover the glottis.
Cough
It clears the lower respiratory tract of foreign material
Sneeze
The same as a cough, but directed through the nasal cavity and clears the upper respiratory tract.
Valsalva
A reflex that creates a pneumatic support when strenuous activities, such as lifting heavy weights, are performed
Partial Pressure
Dalton’s Law. The total pressure exerted by a mixture of gases is equal to the sum of the pressure exerted by each gas
Concetration
Henry’s Law. The concentration of a gas in a liquid is directly proportional to it’s partial pressure
Movement of Gases Across Alveoli
Oxygen diffuses into the pulmonary cavities, CO2 diffuses into the alveoli.
Transport of Respiratory Gases by Blood
O2 has a higher concentration in the blood than in the tissues, and CO2 has a higher concentration in the tissues than in the blood
Hypoxia
Insufficient O2 due to impaired respiration, anemia, heart failure or poisoning.
CO Poisoning
A result of incomplete combustion reactions. The iron in hemoglobin has a higher affinity for CO than O2.
Hypernea
Breath is deeper more vigorous, but the breathing pattern has not changed. Results in increased ventilation.
Chronic Bronchitis
Escessive mucus production. Decreases lung ventilation and gas exchange.
Obstructive Emphysema
Enlargement of alveoli until they are destroyed, this is permanent.
Lung Cancer
3 most common types
- Squamous cell carcinoma: In the major bronchi
- Adenocarcinoma: Nodules found in the peripheral lung area
- Small cell carcinoma: clusters in the mediastinum
Hypoxia
Not enough oxygen
Asthma
An allergic response which is triggered from a spastic contraction of the smooth muscle of the bronchioles
Pulmonary Edema
Accumulation of fluid in the alveoli and the bronchi. Lowers the surface are and the amount of gas exchange
Cystic Fibrosis
A genetic disease where viscous mucus clogs the respiratory passageways
Effects of Aging
Between the ages of 20-70, the main lung capacity will be reduced by 25-30%. Lung elasticity is reduced. Loss in PO2, phagocytic activity, and cilia action.
